Flavor ingredient regulatory record
2-Oxopentanedioic acid
2-Oxopentanedioic acid is an acid in the fruity family, FEMA GRAS under FEMA number 3891 (CAS 328-50-7). Its odor is sour, fruity, tangy, acidic.
- FEMA
- 3891
- CAS
- 328-50-7
- JECFA
- 634
- EU FL
- 08.037
- Formula
- C5H6O5
- EC
- 206-330-3
GRAS status: FEMA GRAS, publication 18. Recorded by FDA in the Substances Added to Food inventory under CAS 328-50-7.
Structure
Identity
Also known as: Pentanedioic acid, 2-oxo-, Glutaric acid, 2-oxo-, α-keto-Glutaric acid, α-Oxoglutaric acid, 2-Oxoglutaric acid, 2-Oxo-1,5-pentanedioic acid, 2-Ketoglutaric acid, α-Ketoglutaric acid, α-Oxopentanedioic acid, NSC 17391, Aladdin K 105571, 2-oxoglutaric acid.
Can 2-Oxopentanedioic acid be labeled natural?
The process decides for 2-Oxopentanedioic acid. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic 2-Oxopentanedioic acid is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
- United States
- Natural or artificial, by process
- European Union and UK
- Natural only from natural material
- Mercosur and Mexico
- Natural or identical-to-natural
How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.
Regulatory status, with citations
United States
2-Oxopentanedioic acid is FEMA GRAS under FEMA number 3891. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
Listed on the Union List of flavouring substances as FL 08.037, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (JECFA). The UK retains the same list.
JECFA (WHO / FAO)
JECFA number 634, evaluated at the 53rd meeting in 1999. No safety concern at current levels of intake when used as a flavouring agent.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. 2-Oxopentanedioic acid appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 328-50-7, where EPA names it Pentanedioic acid, 2-oxo-.
Active in US commerce
EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. What active and inactive mean.
EPA publishes no regulatory flags on this listing. What the flags mean.
From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.
Odor and taste
Odor: Sour, fruity, tangy, acidic.
Where it is used
2-Oxopentanedioic acid is used in beverage, confection, sour candies and fruit flavors, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to 2-Oxopentanedioic acid by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| l-Glutamic acid | 3285 | 90% | In nature |
| 3,4-Dihydroxybenzoic acid | 4430 | 82% | In nature |
| 4-Hydroxybenzoic acid | 3986 | 80% | In nature |
| Aconitic acid | 2010 | 74% | In nature |
| 4-Hydroxy-3-methoxy benzoic acid | 3988 | 74% | In nature |
More acids in this index
Oleic acid · (E,Z)-4-Methylpent-2-enoic acid · 3-Methoxybenzoic acid · trans-4-Octenoic acid · Heptanoic acid · 2-Methylvaleric acid
2-Oxopentanedioic acid FAQ
Is 2-Oxopentanedioic acid FEMA GRAS?
Yes. The FEMA Expert Panel lists 2-Oxopentanedioic acid as GRAS under FEMA number 3891. The Code of Federal Regulations lists it at 21 CFR 172.515.
What are the FEMA and CAS numbers for 2-Oxopentanedioic acid?
2-Oxopentanedioic acid is FEMA 3891, CAS 328-50-7. Its flavor category is fruity.
How is 2-Oxopentanedioic acid described, and where does it show up?
Flavorists describe 2-Oxopentanedioic acid as sour, fruity, tangy, acidic. It is used in beverage, confection, sour candies and fruit flavors.
What did JECFA conclude about 2-Oxopentanedioic acid?
JECFA evaluated 2-Oxopentanedioic acid at the 53rd meeting in 1999 under JECFA number 634. The panel concluded: No safety concern at current levels of intake when used as a flavouring agent.
Is 2-Oxopentanedioic acid on the EU Union List?
Yes. FL 08.037 is the Union List entry for 2-Oxopentanedioic acid, annex I Part A, under Regulation 1334/2008, and the UK keeps the same list.
Does 2-Oxopentanedioic acid count as natural in the US and the EU?
Nature makes 2-Oxopentanedioic acid, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial 2-Oxopentanedioic acid, same molecule. In the EU and UK the natural claim likewise needs the natural route, while Mercosur and Mexico keep a third class, identical-to-natural, for the synthetic material.
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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as 2-OXOPENTANEDIOIC ACID under CAS 328-50-7 and carries its FEMA number, its JECFA flavor number. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.
A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.
Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.
About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.